macro respiration chapter 42. what you need to know the general characteristics of a respiratory...
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What you need to know
The general characteristics of a respiratory surface.
The pathway a molecule of oxygen takes from the air until it is picked up by the hemoglobin of a red blood cell.
Respiration
Uptake of O2 and discharge of CO2 Respiratory Medium is the source of O2
Air (21% O2) Water (varies with temperature and
salinity but always less than 21%) As temp and salinity increase, O2 decreases
Gas diffuses based on gas pressure (partial pressure) Always from high to low (simple diffusion)
Respiratory Surfaces Always moist, single cell layer,
epithelial tissue (skin cells) Lungs, air sacs, trachea
In folding of body/skin *(favorable surface area to volume ratio)
Reduces water loss for terrestrials Gills
Outer folding of body/skin * Countercurrent exchange
Skin
Types of Respiration
1. Skin Breathing (worms) No specialized respiratory surface,
high surface area to body volume required, they have to stay small, must live in moist environments
Types of Respiration
2. Tracheal System (insects) Extensive branching tubes reach every cell, no
circulatory system required, low efficiency, organisms are small and ectothermic
Types of Respiration
3. Gills (organisms) Two or more, countercurrent
exchange, high energy requirement
Types of Respiration
4. Lungs (terrestrial vertebrates)
Large surface area through intense in-folding
Covered with moist epithelial tissue
Human Pulmonary System Flow of air into the body:1. Mouth or nose 2. Pharynx (throat) 3. Epiglottis (skin flap) 4. Larynx (voice box) 5. Trachea (windpipe) 6. Bronchi (2 bronchus: 1 to
each lung) 7. Lungs which contain
bronchioles (small tubules) and alveoli (tiny air sacs at the end of each bronchiole)
Functions of Organs
Nasal cavity: cleans, moisturizes, and warms air
Larynx: sound Epiglottis: separating food from air
Cartilage flap that covers the entrance to the trachea, only opens when you breath
Nervous system cross inhibition prevents swallowing and breathing at the same time
Functions of Organs
Trachea & bronchi: ciliated epithelial cells which secrete mucus to trap and remove any remaining dirt/dust/debris particles Mucus is transported by cilia dispelling
mucus out the throat and nose Cystic fibrosis is a recessive
mutation leading to thick mucus which is a breeding ground for bacteria
Functions of Organs
Lungs: spongy tissue with enormous surface area (football field)
Right lung has 3 lobes, left lung has 2
Surrounded by capillaries Gases pass through 2 cell layers:
alveoli cell and capillary wall cell
Gas Exchange
Alveoli are tiny lung sacs 1 cell layer thick
Gases diffuse from high to low concentrations (higher O2 in alveoli, higher CO2 in the blood)
Gas Transport
Hemoglobin: quaternary protein, iron chelate in vertebrate erythrocytes (RBC)
Myoglobin: similar to hemoglobin, O2 storing protein in muscles
Hemolymph: protein/copper chelate in mollusks and arthropods
Most CO2 is bound in the blood liquid as carbonic acid (HCO3-)
Mechanics of Breathing
Diaphragm is a dome-shaped (relaxed) muscle separating the thorax from the abdomen
When the muscle contracts it flattens, pulling down the lungs, which creates a vaccuum = inhalation
Relaxation of the muscles = exhalation
Vital Capacity = maximum volume of air in lungs
Control
Inovluntary Blood chemistry influences
breathing rate Medulla oblongata (brain stem)
has O2 sensors
Respiratory Diseases Infections: ears, nose, throat, bronchi
(bronchitus), lungs (pneumonia) Allergies: hayfever
Asthma: extreme allergic reaction leading to the constriction of bronchi
Emphysema: repeated infections and irritations leads to the replacement of alveoli with scar tissue CF, smoking, pollution
Lung Cancer: mutated alveoli cells